The purpose of this trial is to assess the non-inferior antiviral activity of GSK1349572 50 mg once daily versus RAL 400mg twice daily over 48 weeks; non-inferiority will also be tested at Week 96. Both GSK1349572 and RAL will be given in combination with fixed-dose dual NRTI therapy (ABC/3TC or TDF/FTC). This study will be conducted in HIV-1 infected ART-naïve adult subjects.